gistfile1.js

$.ajaxSetup({
	cache: true,
	jsonpCallback:function(){
		var key = this.data;
		var h = 0;
		for (var i=0; i < key.length; i++) {
			h = (h + (key.charCodeAt(i)*i)) % 10000;
		}
		console.log(h,key);
		return '_' + h;
	}
});